Method and apparatus for making maps from photographs



Oct 1942- s. c. L WESLEYSMKTH 2,300,326

METHOD AND APPARATUS FOR MAKING MAPS FROM PHOTOGRAPHS Filed March so, 1940 4Sheets-Sheet 1 3mm 3.0, L. Wes lei-ism ifh,

M2 Dor s Wesle sm'rl'h exeeu rix,

Oct. 27, 1942.

METHOD AND APPARATUS FOR MAKING MAPS FROM PHOTOGRAPHS 8. CL L. WESLEYSMITH Fil ed March so, 1940 4 Sheets-Sheet 2 3 s.C.l .Wes\e smhh, deceased b Doris WesIe srnHl 3 8xecu+riy 0 27, 1942. s. c. L. WESLEYSMITH 2,300,326

METHOD AND APPARATUS FOR MAKING MAPS FROM PHOTOGRAPHS -4 Sheets-Sheet s Filed March 30, 1940 2w it,

27, 1942- s. c. QVEZSLEYSMITH 2,300,326

METHOD AND APPARATUS MAKING MAPS FROM PHOTOGRAPHS Filed March so, 1940 4 Sheets-S heet 4 11 Y01 0. r P

S. L .Wes Q3 5 m deeeqsed M) DOFIS Wes \e smf-Hn Patented Oct. 27, 1942 METHOD AND APPARATUS FOR MAKING MARS FROM PHOTOGRAPES Seymour 0. L. Wesleysmith, deceased, late of Washington, D. 0., by May Doris Wesleysmith, executrix, Washington, D. 0.

Application March 30, 1940, Serial No. 327,016

(Cl. 232ll) 14 Claims.

This invention relates to the making of maps from photographs, and more particularly to the plotting of maps from a stereoscopic image formed from pairs of photographs, taken by an airplane in flight.

One object of this invention is to provide a method of mapping whereby a continuous map may be made from a series of partially overlapping aerial photographs.

Another object is to provide an improved method of plotting contours from aerial photographs.

A further object is to provide a device for plotting maps from stereoscopic photographic pairs.

Yet another object is to provide means for carrying control from one photograph into another by stereoscopic fusion.

Still another object is to provide means which will allow the transposition of photographs without need for a multiplicity of measurements.

Yet a further object is to provide an apparatus in which the parts are always centered.

Still another object is to provide means for readily compensating for cant, swing, tilt, dip and variation in azimuth.

A further object is to provide a relatively inexpensive means for attaining the foregoing and other objects.

Other objects and advantages of this invention will appear in the following description taken in connection with the accompanying drawings.

.ihis invention provides an improvement over the prior art, because no other device in this art simultaneously views and plots from two aerial photographs in stereoscopic fusion, making use of the principle that there is no parallax perpendicular to the line of flight, and which in plotting, coordinates and compensates the varying differences of parallax between the two photographs and plots them on a plane coordinate basis in planimetric and/or topographic form.

In accordance with the present invention the photographs are set in rigid geometric correspondence to each other both mutually and externally and the seven spatial settings utilized in attaining this correspondence are not disturbed by the subsequent observational movements.

Other machines which have attempted to accomplish this result plot from either the right or left-hand photograph only, as a result of the geometry of their construction, while viewing the stereoscopic model.

In the drawings wherein like reference characters indicate corresponding parts in the various figures.

one preferred embodiment of the present invention,

Fig. 2 is a schematic view illustrating the operation and construction of the preferred embodiment.

Fig. 3 is a plan view of the parts of the apparatus utilized in supporting the photographs,

Fig. 4 is a vertical section through the photograph supporting means, substantially on a line 4-4 of Fig. 3,

Fig. 5 is a plan view, on an enlarged scale, of one of the photograph holding elements,

Fig. 6 is an enlarged detail view illustrating a simple way of retaining the photographs in compensated position, and corresponding substantially to a vertical section on the line 6-6 of Fig. 5,

Fig. '7 is a vertical section showing a variation in the manner of supporting the photograph holders,

Fig. 8 illustrates a variation in the optical system wherein the simple stereoscope parts are mounted in one structure and various lenses are arranged in a separate binocular element cooperating with the stereoscope,

Fig; 9 shows a variation in the construction of Fig. 1 whereby contour intervals may be directly measured by the stereoscopic image,

Fig. 10 is an enlarged partial section through the photograph support of Fig. 9 and illustrating a variation of the arrangement of Fig. 1,

Fig. 11 is a vertical section on the line l l--! I of Fig. 10.

Generally speaking the invention contemplates a simple method and means togeometrically plot observed points either planimetrically or contouring topographically by the utilization of a constant base datum and utilizing equal angles from the vertical in the reflecting mirrors or prisms. 'I'he invention also contemplates a simple and direct method and means to progress from one photograph to another while carrying ground control through a series of photographs.

Considering the drawings in greater detail, the invention contemplates a relatively inexpensive system which can be placed upon any plotting table 20 and utilized to produce 'accurate maps from -a series of partially overlapping aerial photographs. I

This device in one preferred embodiment contemplates a table 0 which rests upon a plotting table 2!! and which is provided with a transversely extending groove or slot 2| in which is slidably positioned a second table B. Table B has a Fig. 1 is a partial perspective view illustrating slot 22 extending at right angles to the previous- 1y described slot and arranged to receive a table A, which can move therein transversely of table B. Table A is provided with a turntable 23 which is arranged to rotate about its own center 24. Two additional turntables 25 and 26 are mounted upon the table 23 and arranged to rotate about their own respective axes 21 and 28. Photographs 29 and 30 can be secured to these turntables and supported thereon for observation under the stereoscope to obtain the stereoscopic image.

A plotting sheet 3| is mounted on the plotting table and a recording pencil 32 is connected to the axis 24 of the turntable 23 so that movements along the line of flight, and those transversely of the line of flight, corresponding to the movements of thetables B and A, respectively, are transmitted to the pencil 32 to record features of the stereoscopic image either planimetrically or by topographic contours on the record sheet 3|. The pencil may be connected to the point 24 so as to provide an appropriate ratio of movement with respect to the plotting paper 3| so that a map to an appropriate scale may be directly plotted.

In Fig. 1 a simple pantograph 33 is illustrated for this purpose having a fixed point 34 on the plotting table and a movable point 35 connected by means 36 to the axis 24 of turntable 23. The arms 31 and 38 of the pantograph are pivotally connected at 39, the arms 40 and 4| are pivotally interconnected at 42, and the two sets of arms are pivotally connected at 43 and 44, and variably by means of suitable adjustment openings 45.

For the purpose of mechanically developing the stereoscopic image, an optical system or stereoscope 46 is supported on table C by the upright rods or supports 4'! and 48. The optical system is rigidly, although adjustably, secured to the supporting rods by transversely extending members 49 and 50, which latter are secured to the end walls of the housing of the optical system. Appropriate eye-pieces 52 and. 53 are located on the top of the optical system, and viewing apertures 54 and 55 are provided in the body of the housing for viewing the image.

Between the eye-pieces and viewing apertures, as observed in Fig. 1, a magnifying optical stereoscope is interposed. In Fig. 2, this system is illustrated as comprising fixed prisms or reflecting mirrors 56 and 51 which change the direction of the line of sight and movable prisms or mirrors 58 and 59 which throw the line of sight at different points on the photographs, in the direction of the line of flight. Eye-pieces 52 and 53 may be of the prismatic binocular type and the optical elements 66 and 6| may be objectives of a binocular telescope. These elements could also be interposed between the prisms 56 and the eye-pieces 52 thereby using an ordinary binocular telescope construction. Engraved crosses on a piece of optical glass or cross hairs as in a transit telescope construction are arranged at 62 and 63 for the purpose of studying the stereoscopic image. Magnifying lenses 64 and 65 may be inserted between the reflecting mirrors and the viewing apertures for the purpose of magnifying the image. These members 64 and 65, when used, will be interconnected by a simple linkage so that a ray from the mirrors 58'and 59 always passes close to the nodal point.

In Fig. 8 the optical system is simplified in one respect so that the housing 46 contains only a relatively simple stereoscope and the various optical elements of the system are transposed into separable binocular elements 66 which can be constructed to cooperate with the eye-pieces 52 and 53. In Fig. 2 the elements 64 and 65 are shown in dotted position at 64 and 65', indicating a movement corresponding to the linkage operation to maintain the optical elements accurately in the line of sight. These latter elements may be omitted in connection with the less expensive forms of apparatus.

The reflecting mirrors or prisms 58 and 59 are rotatably supported within the housing and arranged to rotate about their respective axes 61 and 68. The reflecting elements are mounted on bearings with wheels 69 and I0 and a metal band H passed around the periphery of the wheels so that when rotating the mirrors the angles 12 and 13 will always be equal and the base line 14 will always extend at right angles to the vertical axis 15 of the optical system. A small hand wheel 16 may extend out of the housing 46 and provide the necessary means for manually varying the angularity of the reflecting mirrors and thereby allow the observer to move the line of sight, along the line of flight, in the two supported photographs. This can be accomplished in the simplest form by a wheel frictionally engaging the rim or periphery of wheel 10.

The entire optical system may be raised or lowered on the supports 41 and 48, when desired Although a very simple construction is shown as to this feature, the parts will be arranged to eliminate any flexure.

The movement of table B upon table C is in the direction of the line of flight.

In Figs. 4 and '7, two variations in the arrangement of the turntables are illustrated.

In Fig. 4 the small turntables 25 and 26 have beveled outer edges 11 arranged to rotate in the beveled sockets or bearings 18 carried in the large turntable 23. The latter is also provided with a beveled periphery 19 which is arranged to ride on the beveled surface 80. All wear in the photograph holding tables will be upon the beveled or tapered surfaces and they will remain centered on their respective axes at all times during the useful life of the equipment.

In Fig. '7 a similar result is attained. but in this instance the small turntables are each provided with a depending boss 8| in the form of a conical surface which is arranged to sit in conical recesses of the turntable 23. A similar bearing is provided at 82 between the large turntable and the supporting table A. Both of these structural arrangements preserve the centered alignment of the photograph supports at all times.

In Figs. 5 and 6 one arrangement is illustrated whereby the photographs can be mounted for complete compensation of irregularities in the photographs resulting from the swing of the airplane along the line of flight; cant of the airplane in the line of flight; differential tilt as between two photographs, variation in elevation between photographs; variation in azimuth of the air base or datum of the optical system during flight; orientation of the stereoscopic image or model in the canting sense; and orientation of the stereoscopic image or model in the tilt ing sense.

The small turntable 25 is provided with a map supporting surface 83 which may be supported by a gimbal construction to provide universal mounting. The map supporting table 83 is mounted for movement about an axis 84-extending at right angles to the line of flight.-- The ring 85 supporting the last named axis is arranged to rotate about an axis 86 along the line of fiight. These axes are provided by means ofsuitable spindles 8'! which extend from one of the elements and are supported in bearings carried by the other.

As there is very little load upon the foregoing parts they can be arranged to retain their ad- Justed positions by friction alone. However, it is preferable to provide some means for locking the photographs in adjusted position" and a simple arrangement would be a thumb nut and pivoted clamp 89 to lock the spindle in position. Two of these can be provided, one at 99 along the one axis and another at 9| on the remaining axis.

In the continuous plotting along a line of flight it is necessary to form the stereoscopic image from a continuing series of photographs It is also necessary to carry control through this continuous series of photographs without having to make a number of complicated mathematical measurements and calculations. In Fig. 3 the manner of accomplishing this is illustrated. The first photograph 29 is set up on the table 25 in its proper space relationship corresponding to the position of the camera plate at the time the photograph was taken. The next photograph is mounted in a similarly corrected manner on the table 26. Stereoscopic fusion having been obtained and the map data plotted for the particular image being viewed, the turntable 23 is then rotated 180 about its own axis and the Vernier 92 on the turntable 23 aligned with corresponding scale 93 on the table A. The photographs are now reversed in position. The turntable 26 then assumes the original position of turntable 25 and vice versa. The turntable '26 in its new position is now rotated 180 about its own axis and then properly aligned by a scale 94. This series of operations places the photograph 30 in the position originally occupied by photograph 29. The photograph 29 can now be removed from the apparatus and a newphotograph substituted and the new stereoscopic image utilized for plotting the next portion of the map. This procedure is continued until the entire flight series has been transformed into a map of the type desired.

As a result of the apparatus described the planimetric projection of a point M on the two photographs will always lie along a perpendicular from N to the line El and E2 and bisect the same. The mirrors 58 and 59' are set and angles they make with the base El and B2 are not changed. If the mark 62-63 is now maintained in contact with a ground formation in the image, a line of equal elevation or contour isobtained and can be plotted. By varying the angle of vision different elevations can be traced and roads followed and by determining the variation in the angles by the system in Fig. 9 the elevation can be measured directly. In Fig.2 the photographs 29 and 3e are supported upon turntables 25 and 26, with the single line in Fig. 2 representing the surface of theph'otograph. In this figure the rotation of eachphotograph about its optical axes a-b (BL-28') compensatesfor the swing which may exist in the different aerial photographs. The fore and aft movement of the optical axis inthe base plane containing contour interval or elevation.

its principal points is the correction for eant and is accomplished along the axis a-'c. R'otation of onephotograph with'respect tothe other along the axis of the air base is known as differential tilt and is c'orrectedby the lin'etaa. The difference in elevation of the photographs at the terminals of the air base as compared with the datum plane is corrected by (1-11. The correction for change in azimuth of the air base is accomplished with respect to az. The intersecting centers of movement of the tables at a-a are-interconnected by rods which in turn extend into a sleeve 36 wherein they can be secured-by thumb nuts 91. This arrangement allows the various corrections heretofore described to be attained while at the same time maintaining the proper alignment of the photographs with the optical system.

By placing a piece of Celluloid over the map three to five points may be located and the Celluloid reversed and checked with the map and if correct the left hand photograph can now be removed and the photograph substituted. This will allow the carryingof' control through the entire series.

The'grooves 2'! and ZZwill preferably be tapered to assure continuous correct alignment of the parts although it will readily be understood that the taper may be reversed.

In Fig. 9 the relative movements of the system 'are somewhat reorganized to attain'certainresults. In this variation table B is provided at its sides with tracks 98 so that the supporting rods 41 and 88 may move transversely of the table.

This movement will be at right angles to the line of flight. Frame work 99 is fixed to the optical system and extends just above the table B and is interconnected'by rods or other members l'llfl which carry a carriage IEH. This carriage is arranged to move along the rods and since the relative movement necessary for working may be limited to about 8" each way there is no danger of fiexure taking place; The pencil 32' is connected to the carriage by-an arm I 92 to transmit the movement to the map.

The carriage llll has on its upper surface oppositely facing channel members I03 and-I04 which form a slide bearing. A member 15".lS arranged to ride vertically in this bearing and is provided with a thumb screw, not shown, to'lock it at any desired position. Scale marks I06 on the channels provide the means whereby the vertical m'ovement'of the bearing M5 can be accurately measured. Such movement measures In this construction a pair of shafts Ill! and H78 are carried on the housing 46 and discs I09 and Hi] can be mounted on the shafts. discs are arranged to be driven from the wheels 69 and H3 in a ratio preferably of one to two so that the discs IE9 turn twice as fast as the wheels. The outer surface of each of these discs supports a plurality, of rotatable bearings Ill through whichrods H2 can frictionally pass.

These 'rodsare pivotally connected to the bearing elements are at H3. Observation of the stereoscopic image is'now transformed by means of: the rods into the movement of the bearing H25 50' that a difference, in reading on scale I06 Thesemovement will correspond to points of constant elevation.

The photograph holding tables 26' and 25' in Fig. 9 are mounted upon movable slide blocks H4 which are arranged to ,move between the tapered rods H5 supported in the table 23. Table 25 is mounted by an adjustable screw H6 so that differences in elevation of the photographs can be immediately compensated.

As the vertical movement of these tables is in respect to the movable optical system the tables for this variation need not be interconnected by rods as in Fig. 2. Furthermore, the screw H6 may preferably have a slotted collar arrangement or be grooved so that the table will not rotate while being raised or lowered. A thumb wheel H1 raises or lowers the table and a pin and slot H8 prevents rotation.

Although a preferred embodiment of this invention is illustrated and described, variations within the true spirit and scope of the same are to be determined by the appended claims.

What is claimed is:

1. The method of making contour or other maps comprising matching pairs of displaced photographs to form stereoscopic images, comprising rotating the photographs in space about a common central axis, rotating each photograph about its own axis, and consecutively substituting additional photographs in place of one of the preceding pair of photographs whereby to progressively form a continuous space image of a .photographed area.

2: An apparatus for making planometric maps of ground areas from aerial photographs comprising a frame, a table slidably mounted on said frame for movement along one axis, a second table slidably mounted on the first table upon an axis at right angles to the movement of the first table, means mounted on the second table arrangedto hold spacially displaced photographs, means for rotating said photographsabout a central common axis, means for plotting in accordance with a stereoscopic image of the photographed areas, and a binocular stereoscope including reflecting means rotatably mounted on parallel axes and means for rotating said means in opposite directions about their respective axes and through the same respective angles of movement.

3. The method of plotting a map from a series of aerial photographs by means of a fused stereoscopic image, comprising reversing the position of the image creating photographs, and substituting a new photograph for one of the reversed photographs to spacially move the stereoscopic image along the line of flight.

4. A stereoscope comprising photograph supporting tables having universal movement about a nodal point, an optical system for viewing photographs, means for rotating the tables about the axis of the optical systems, and means for scanning various portions of the stereoscopic image without moving the photograph.

5. A stereoscopic mapping means comprising aturntable rotatable upon an axis, photograph supporting tables mounted thereon and spacially centered with respect to the turntable axis, and means on the mating surfaces of the tables to maintain said tables centered irrespective of the wear of said surfaces.

6. The device of claim 5 wherein the tables are relatively adjustable.

7. The device of claim 5 wherein the last named 1 means comprises tapered'bearings.

8. A stereoscope comprising an optical system for viewing spaced stereo photographs comprising spaced reflecting mirrors mounted upon parallel axes extending through the centers of their optical system, a disc connected to each mirror, means for rotating a disc, and a continuous band extending around the periphery of each disc, and arranged to simultaneously rotate the mirrors through equal opposite angles.

9. An apparatus for making planometric maps of ground areas from aerial photographs, a binocular stereoscope including reflecting elements rotatably mounted on parallel axes, means for rotating said elements in opposite directions about their respective axes, means for measuring variations in elevation of points on the stereoscopic image including rotating discs arranged to rotate in response to the movement of said reflecting means and in the relation of twice the angular movement thereof, spaced bearings on each-of said discs, pivoted rods slidably supported in said bearings, means supported on said frame for retaining the pivoted connection and said rods in a common plane, and means for transforming the movement of said pivoted connection into a visual record.

10. An apparatus for making planometric maps of ground areas from aerial photographs comprising a frame, a table slidably mounted on said frame for movement along one axis, a second table slidably mounted on the first table upon an axis at right angles to the movement of the first table, means mounted on the second table arranged to hold spacially displaced photographs, means for rotating said photographs about a central common axis, means for plotting in. accordance with a stereoscopic image of the photographed areas, and a stereoscope including reflecting elements rotatably mounted, and means forrotating' said elements in opposite directions about their respective axes and through the same respective angles of movement.

11. An apparatus for making planometric maps of ground areas from aerial photographs comprising a frame, a table slidably mounted on said frame for movement along one axis, a second table slidably mounted on the first table upon an axis at right angles to the movement of the first table, means mounted by tapered bearing surfaces on the second table arranged to hold spacially displaced photographs, means having tapered surfaces for rotating said photographs about a central common axis, means for plotting in accordance with a stereoscopic image of the photographed areas, and a stereoscope including reflecting elementsand means for rotating said elements about their respective axes.

12. An apparatus for making planometric maps of ground areas from aerial photographs comprising a frame, a table slidably mounted on said frame for movement along one axis, a second table slidably mounted on the first table upon an axis at right angles to the movement of the first table, means mounted on the second table arranged to hold spacially displaced photographs, means for rotating said photographs abouta central common axis, means for rotating each photograph about its own axis, means for plotting in accordance with a stereoscopic image of the photographed areas, and a stereoscope including reflecting means for viewing said photographs stereoscopically.

13. A stereoscopic mapping means comprising a turntable having a tapered periphery, and rotatable upon an axis, photographsupporting tables spacially mounted thereon and having complemental tapered supporting surfaces, whereby wear of the parts maintain said tables always centered, a stereoscopic optical system for viewing the photographs, and means for plotting in accordance with the stereoscopic image of the photographed areas.

14. A stereoscopic mapping means comprising a turntable having a tapered periphery and rotatable upon an axis, photograph supporting tables spacially mounted thereon and having tapered supporting surfaces, whereby wear of the parts maintain said tables always centered, a stereoscopic optical system for viewing the photographs, and means for pldtting in accordance with the stereoscopic image of the photographed areas, and means for moving; the optical system and the photograph relative to each other.

MAY DORIS VKEESLEYSMITH,

Zeysmith, Deceased. 

